Personal care composition

ABSTRACT

A personal care composition comprising a eutectic mixture, the eutectic mixture comprising a tertiary system, in which menthol may form part of the eutectic mixture or in the eutectic mixture comprises an antidandruff agent such as ketoconazole.

This invention relates hair/scalp care compositions and in particular to hair and/or scalp care compositions. The invention also relates to the use of these compositions for the treatment and/or prevention of inflammatory skin conditions such as scalp itch and dandruff.

Many hair/scalp care compositions are used to deposit benefit agents on the skin/scalp or hair, however efficient deposition of these benefit agents can pose a problem, especially in rinse off compositions.

Eutectic mixtures have been used in WO 98/51283 to aid the transdermal delivery of a pharmacologically active drug.

Eutectic mixtures of active substances, such as local anaesthetic mixtures, are described for use in pharmaceutical and cosmetic compositions in WO 2005/018530. Such mixtures are said to provide an improved dermal penetration profile.

The present inventors have found that certain eutectic mixtures can be used to enhance deposition of benefit agents, in particular benefit agents that prevent the occurrence of symptoms of dandruff such as scalp skin itching and flaking.

According to the invention there is provided a hair/scalp care composition comprising a eutectic mixture, the eutectic mixture comprising an antidandruff agent, also described is a method of treating the scalp or hair which comprises the step of applying to the hair a composition comprising a eutectic mixture, the eutectic mixture comprising an antidandruff agent.

In another aspect the invention relates to a method of depositing an antidandruff agent onto the scalp or skin in which the antidandruff agent is in the form of a eutectic mixture.

The invention also relates to a method of mitigating dandruff comprising the step of applying to the hair and/or scalp a composition as described above.

A eutectic mixture of two or more eutectic-forming solids shows, upon intimate admixture of the solids, a homogeneous liquid phase above the melting point of the higher melting component. A plot of melting point versus relative composition of the two eutectic-forming solids displays a minimum point between two intersecting lines at which a homogeneous liquid phase coexists with each of the respective homogeneous solid phases. This point is known as the eutectic point or eutectic temperature.

The present invention relates to a eutectic mixture of ingredients that comprise an antidandruff agent.

Preferably the composition comprises menthol. Menthol is preferably present in the total composition at a level from 0.001 to 5 wt %, more preferably from 0.01 to 2 wt %

Preferably the eutectic mixture further comprises an anti-dandruff agent at levels from 0.01% to 30% by weight, more preferably 0.05% to 10%, most preferably 0.1 to 2% by weight of the total composition. Antidandruff agents are compounds that are active against dandruff and are typically antimicrobial agents, preferably antifungal agents.

Antifungal agents typically display a minimum inhibitory concentration of about 50 mg/ml or less against Malassezia.

Suitable antidandruff agents include compounds selected from ketoconazole, climbazole, octopirox, zinc pyrithione, and mixtures thereof.

The preferred antifungal agents are azole based. Of particular importance are ketoconazole and climbazole, ketaconazole being particularly preferred. These antidandruff agents give particularly good antimicrobrial results when used in a eutectic mixture.

A further component that is advantageous when used in the eutectic mixture is an organic acid. Preferred organic acids are lactic acid, glycolic acid, hydroxy acids (in particular citric, tartaric, malic), fatty acids, galacturonic acid, gluconic acid, amino acids, hydroxyoctanoic acid, adipic acid, benzoic acid, and hydroxybenzoic and dihydroxybenzoic acids.

Particularly preferred organic acids are selected from the list consisting of salicylic acid, benzoic acid and mixtures thereof.

As an alternative to the organic acids mentioned above the eutectic mixture may comprise catechol and/or chysin.

A eutectic mixture comprising a tertiary system is particularly preferred.

It is preferred if the molar ratio of azole based antidandruff agent/menthol/organic acid within the eutectic mixture is from 0.1:1:1 to 2:1:1, and preferably from 0.1:1:1 to 1:1:1.

Preferred eutectic mixtures increase active solubility in product formulations and deposition efficiency. Eutectic mixtures comprising an antidandruff agent give increased bioavailability and increase efficacy (Malassezia kill).

Compositions of the present invention are typically hair care/scalp care compositions. They may be formulated as transparent or opaque emulsions, lotions, creams, pastes or gels.

Hair and/or scalp care compositions of the invention may be rinse off products or leave on products. Leave on products are intended not to be rinsed off the hair and/or the scalp of the user immediately after use (i.e., within at least the first two hours, preferably at least four hours, after application of the composition). Leave on products include, for example, lotions, creams and hair oils that are intended for topical application to the hair and/or the scalp. Rinse off products are intended to be substantially rinsed off the hair and/or the scalp of the user with water after use.

Rinse off compositions include shampoos and hair conditioners, as well as hair and/or scalp treatment products which are intended to be left on the hair and/or scalp for up to half an hour, preferably 5 minutes, before being rinsed off.

Preferred product forms are shampoos and conditioners. Rinse off compositions are preferred.

Shampoo compositions according to the invention will typically comprise one or more anionic cleansing surfactants which are cosmetically acceptable and suitable for topical application to the hair.

Anionic Cleansing Surfactant

Examples of suitable anionic cleansing surfactants are the alkyl sulphates, alkyl ether sulphates, alkaryl sulphonates, alkanoyl isethionates, alkyl succinates, alkyl sulphosuccinates, N-alkyl sarcosinates, alkyl phosphates, alkyl ether phosphates, alkyl ether carboxylates, and alpha-olefin sulphonates, especially their sodium, magnesium, ammonium and mono-, di- and triethanolamine salts. The alkyl and acyl groups generally contain from 8 to 18 carbon atoms and may be unsaturated. The alkyl ether sulphates, alkyl ether phosphates and alkyl ether carboxylates may contain from 1 to 10 ethylene oxide or propylene oxide units per molecule.

Typical anionic cleansing surfactants for use in shampoo compositions of the invention include sodium oleyl succinate, ammonium lauryl sulphosuccinate, ammonium lauryl sulphate, sodium dodecylbenzene sulphonate, triethanolamine dodecylbenzene sulphonate, sodium cocoyl isethionate, sodium lauryl isethionate and sodium N-lauryl sarcosinate. The most preferred anionic surfactants are sodium lauryl sulphate, sodium lauryl ether sulphate(n)EO (where n ranges from 1 to 3), ammonium lauryl sulphate and ammonium lauryl ether sulphate(n)EO (where n ranges from 1 to 3).

Mixtures of any of the foregoing anionic cleansing surfactants may also be suitable.

The total amount of anionic cleansing surfactant in shampoo compositions of the invention is generally from 5 to 30, preferably from 6 to 20, more preferably from 8 to 16 percent by weight of the composition.

Co-Surfactant

Shampoo compositions according to the invention can optionally include co-surfactants, to help impart aesthetic, physical or cleansing properties to the composition.

A preferred example is an amphoteric or zwitterionic surfactant, which can be included in an amount ranging from 0 to about 8, preferably from 1 to 4 wt %.

Examples of amphoteric and zwitterionic surfactants include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulphobetaines (sultaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphopropionates, alkylamphoglycinates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, wherein the alkyl and acyl groups have from 8 to 19 carbon atoms. Typical amphoteric and zwitterionic surfactants for use in shampoos of the invention include lauryl amine oxide, cocodimethyl sulphopropyl betaine and preferably lauryl betaine, cocamidopropyl betaine and sodium cocamphopropionate.

Another preferred example is a nonionic surfactant, which can be included in an amount ranging from 0 to 8, preferably from 2 to 5 percent by weight of the composition.

For example, representative nonionic surfactants that can be included in shampoo compositions of the invention include condensation products of aliphatic (C₈-C₁₈) primary or secondary linear or branched chain alcohols or phenols with alkylene oxides, usually ethylene oxide and generally having from 6 to 30 ethylene oxide groups.

Other representative nonionic surfactants include mono- or di-alkyl alkanolamides. Examples include coco mono- or di-ethanolamide and coco mono-isopropanolamide.

Further nonionic surfactants which can be included in shampoo compositions of the invention are the alkyl polyglycosides (APGs). Typically, the APG is one which comprises an alkyl group connected (optionally via a bridging group) to a block of one or more glycosyl groups. Preferred APGs are defined by the following formula: RO-(G)_(n) wherein R is a branched or straight chain alkyl group which may be saturated or unsaturated and G is a saccharide group.

R may represent a mean alkyl chain length of from about C₅ to about C₂₀. Preferably R represents a mean alkyl chain length of from about C₈ to about C₁₂. Most preferably the value of R lies between about 9.5 and about 10.5. G may be selected from C₅ or C₆ monosaccharide residues, and is preferably a glucoside. G may be selected from the group comprising glucose, xylose, lactose, fructose, mannose and derivatives thereof. Preferably G is glucose.

The degree of polymerisation n may have a value of from about 1 to about 10 or more. Preferably, the value of n lies in the range of from about 1.1 to about 2. Most preferably the value of n lies in the range of from about 1.3 to about 1.5.

Suitable alkyl polyglycosides for use in the invention are commercially available and include for example those materials identified as: Oramix NS10 ex Seppic; Plantaren 1200 and Plantaren 2000 ex Henkel.

Other sugar-derived nonionic surfactants which can be included in shampoo compositions of the invention include the C₁₀-C₁₈ N-alkyl (C₁-C₆) polyhydroxy fatty acid amides, such as the C₁₂-C₁₈ N-methyl glucamides, as described for example in WO 92 06154 and U.S. Pat. No. 5,194,639, and the N-alkoxy polyhydroxy fatty acid amides, such as C₁₀-C₁₈ N-(3-methoxypropyl) glucamide.

A preferred blend of cleansing surfactants is a combination of ammonium lauryl ether sulphate, ammonium lauryl sulphate, PEG 5 cocamide and cocamide MEA (CTFA designations).

The shampoo composition can also optionally include one or more cationic co-surfactants included in an amount ranging from 0.01 to 10, more preferably from 0.05 to 5, most preferably from 0.05 to 2 percent by weight of the composition. Useful cationic surfactants are described herein below in relation to conditioner compositions.

The total amount of surfactant (including any co-surfactant, and/or any emulsifier) in shampoo compositions of the invention is generally from 5 to 50, preferably from 5 to 30, more preferably from 10 to 25 percent by weight of the composition.

Cationic Polymer

A cationic polymer is a preferred ingredient in shampoo compositions according to the invention, for enhancing conditioning performance of the shampoo.

The cationic polymer may be a homopolymer or be formed from two or more types of monomers. The molecular weight of the polymer will generally be between 5 000 and 10 000 000, typically at least 10 000 and preferably in the range 100 000 to about 2 000 000. The polymers will have cationic nitrogen containing groups such as quaternary ammonium or protonated amino groups, or a mixture thereof.

The cationic nitrogen-containing group will generally be present as a substituent on a fraction of the total monomer units of the cationic polymer. Thus when the polymer is not a homopolymer it can contain spacer non-cationic monomer units. Such polymers are described in the CTFA Cosmetic Ingredient Directory, 3rd edition. The ratio of the cationic to non-cationic monomer units is selected to give a polymer having a cationic charge density in the required range. Suitable cationic conditioning polymers include, for example, copolymers of vinyl monomers having cationic amine or quaternary ammonium functionalities with water soluble spacer monomers such as (meth)acrylamide, alkyl and dialkyl (meth)acrylamides, alkyl (meth)acrylate, vinyl caprolactone and vinyl pyrrolidine. The alkyl and dialkyl substituted monomers preferably have C1-C7 alkyl groups, more preferably C1-3 alkyl groups. Other suitable spacers include vinyl esters, vinyl alcohol, maleic anhydride, propylene glycol and ethylene glycol.

The cationic amines can be primary, secondary or tertiary amines, depending upon the particular species and the pH of the composition. In general secondary and tertiary amines, especially tertiary, are preferred.

Amine substituted vinyl monomers and amines can be polymerized in the amine form and then converted to ammonium by quaternization.

The cationic conditioning polymers can comprise mixtures of monomer units derived from amine- and/or quaternary ammonium-substituted monomer and/or compatible spacer monomers.

Suitable cationic conditioning polymers include, for example:

-   -   copolymers of 1-vinyl-2-pyrrolidine and         1-vinyl-3-methyl-imidazolium salt (e.g. chloride salt), referred         to in the industry by the Cosmetic, Toiletry, and Fragrance         Association, (CTFA) as Polyquaternium-16. This material is         commercially available from BASF Wyandotte Corp. (Parsippany,         N.J., USA) under the LUVIQUAT tradename (e.g. LUVIQUAT FC 370);     -   copolymers of 1-vinyl-2-pyrrolidine and dimethylaminoethyl         methacrylate, referred to in the industry (CTFA) as         Polyquaternium-11. This material is available commercially from         Gaf Corporation (Wayne, N.J., USA) under the GAFQUAT tradename         (e.g., GAFQUAT 755N);     -   cationic diallyl quaternary ammonium-containing polymers         including, for example, dimethyldiallyammonium chloride         homopolymer and copolymers of acrylamide and         dimethyldiallylammonium chloride, referred to in the industry         (CTFA) as Polyquaternium 6 and Polyquaternium 7, respectively;     -   mineral acid salts of amino-alkyl esters of homo- and         co-polymers of unsaturated carboxylic acids having from 3 to 5         carbon atoms, (as described in U.S. Pat. No. 4,009,256);     -   cationic polyacrylamides (as described in WO95/22311).

Other cationic conditioning polymers that can be used include cationic polysaccharide polymers, such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum derivatives. Suitably, such cationic polysaccharide polymers have a charge density in the range from 0.1 to 4 meq/g.

Cationic polysaccharide polymers suitable for use in compositions of the invention include those of the formula: A-O—[R—N⁺(R¹)(R²)(R³)X⁻], wherein: A is an anhydroglucose residual group, such as a starch or cellulose anhydroglucose residual. R is an alkylene, oxyalkylene, polyoxyalkylene, or hydroxyalkylene group, or combination thereof. R¹, R² and R³ independently represent alkyl, aryl, alkylaryl, arylalkyl, alkoxyalkyl, or alkoxyaryl groups, each group containing up to about 18 carbon atoms. The total number of carbon atoms for each cationic moiety (i.e., the sum of carbon atoms in R¹, R² and R³) is preferably about 20 or less, and X is an anionic counterion.

Cationic cellulose is available from Amerchol Corp. (Edison, N.J., USA) in their Polymer JR (trade mark) and LR (trade mark) series of polymers, as salts of hydroxyethyl cellulose reacted with trimethyl ammonium substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 10. Another type of cationic cellulose includes the polymeric quaternary ammonium salts of hydroxyethyl cellulose reacted with lauryl dimethyl ammonium-substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 24. These materials are available from Amerchol Corp. (Edison, N.J., USA) under the tradename Polymer LM-200.

Other suitable cationic polysaccharide polymers include quaternary nitrogen-containing cellulose ethers (e.g. as described in U.S. Pat. No. 3,962,418), and copolymers of etherified cellulose and starch (e.g. as described in U.S. Pat. No. 3,958,581).

A particularly suitable type of cationic polysaccharide polymer that can be used is a cationic guar gum derivative, such as guar hydroxypropyltrimonium chloride (commercially available from Rhone-Poulenc in their JAGUAR trademark series).

Examples are JAGUAR C13S, which has a low degree of substitution of the cationic groups and high viscosity. JAGUAR C15, having a moderate degree of substitution and a low viscosity, JAGUAR C17 (high degree of substitution, high viscosity), JAGUAR C16, which is a hydroxypropylated cationic guar derivative containing a low level of substituent groups as well as cationic quaternary ammonium groups, and JAGUAR 162 which is a high transparency, medium viscosity guar having a low degree of substitution.

Preferably the cationic conditioning polymer is selected from cationic cellulose and cationic guar derivatives. Particularly preferred cationic polymers are JAGUAR C13S, JAGUAR C15, JAGUAR C17 and JAGUAR C16 and JAGUAR C162.

The cationic conditioning polymer will generally be present in compositions of the invention at levels of from 0.01 to 5, preferably from 0.05 to 1, more preferably from 0.08 to 0.5 percent by weight of the composition.

When cationic conditioning polymer is present in a shampoo composition according to the invention, it is preferred if the copolymer is present as emulsion particles with a mean diameter (D_(3,2) as measured by light scattering using a Malvern particle sizer) of 2 micrometers or less.

Compositions in accordance with the invention may also be formulated as conditioners for the treatment of hair (typically after shampooing) and subsequent rinsing.

Hair conditioner compositions according to the invention will suitably comprise a cationic conditioning surfactant that is cosmetically acceptable and suitable for topical application to the hair.

Cationic Conditioning Surfactant

Examples of suitable cationic conditioning surfactants are those corresponding to the general formula: [N(R₁)(R₂) (R₃)(R₄)]⁺(X)⁻ in which R₁, R₂, R₃, and R₄ are independently selected from (a) an aliphatic group of from 1 to 22 carbon atoms, or (b) an aromatic, alkoxy, polyoxyalkylene, alkylamido, hydroxyalkyl, aryl or alkylaryl group having up to 22 carbon atoms; and X is a salt-forming anion such as those selected from halogen (e.g. chloride, bromide), acetate, citrate, lactate, glycolate, phosphate nitrate, sulphate, and alkylsulphate radicals.

The aliphatic groups can contain, in addition to carbon and hydrogen atoms, ether linkages, and other groups such as amino groups. The longer chain aliphatic groups, e.g., those of about 12 carbons, or higher, can be saturated or unsaturated.

Preferred cationic conditionings surfactants are monoalkyl quaternary ammonium compounds in which the alkyl chain length is C16 to C22.

Other preferred cationic conditioning surfactants are so-called dialkyl quaternary ammonium compounds in which R1 and R2 independently have an alkyl chain lengths from C16 to C22 and R3 and R4 have 2 or less carbon atoms.

Examples of suitable cationic surfactants include: cetyltrimethylammonium chloride, behenyltrimethylammonium chloride, cetylpyridinium chloride, tetramethylammonium chloride, tetraethylammonium chloride, octyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octyldimethylbenzylammonium chloride, decyldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, didodecyldimethylammonium chloride, dioctadecyldimethylammonium chloride, tallowtrimethylammonium chloride, cocotrimethylammonium chloride, PEG-2 oleylammonium chloride and salts of these where the chloride is replaced by halogen (e.g. bromide), acetate, citrate, lactate, glycolate, phosphate nitrate, sulphate, or alkylsulphate. Further suitable cationic surfactants include those materials having the CTFA designations Quaternium-5, Quaternium-31 and Quaternium-18. Mixtures of any of the foregoing materials may also be suitable. A particularly useful cationic conditioning surfactant is cetyltrimethylammonium chloride, available commercially, for example as GENAMIN CTAC, ex Hoechst Celanese.

Salts of primary, secondary, and tertiary fatty amines are also suitable cationic conditioning surfactants. The alkyl groups of such amines preferably have from about 12 to about 22 carbon atoms, and can be substituted or unsubstituted.

Particularly useful are amido substituted tertiary fatty amines. Such amines, useful herein, include stearamidopropyldiethylamine, stearamidoethyldiethylamine, stearamidoethyldimethylamine, palmitamidopropyldimethylamine, palmitamidopropyldiethylamine, palmitamidoethyldiethylamine, palmitamidoethyldimethylamine, behenamidopropyldimethylamine, behenamidopropyldiethylamine, behenamidoethyldiethylamine, behenamidoethyldimethylamine, arachidamidopropyldimethylamine, arachidamidopropyldiethylamine, arachidamidoethyldiethylamine, arachidamidoethyldimethylamine, diethylaminoethylstearamide. Also useful are dimethylstearamine, dimethylsoyamine, soyamine, myristylamine, tridecylamine, ethylstearylamine, N-tallowpropane diamine, ethoxylated (with 5 moles of ethylene oxide) stearylamine, dihydroxyethylstearylamine, and arachidyl behenylamine. These amines are typically used in combination with an acid to provide the cationic species.

The preferred acid useful herein includes L-glutamic acid, lactic acid, hydrochloric acid, malic acid, succinic acid, acetic acid, fumaric acid, tartaric acid, citric acid, L-glutamic hydrochloride, and mixtures thereof; more preferably L-glutamic acid, lactic acid, citric acid. Cationic amine surfactants included among those useful in the present invention are disclosed in U.S. Pat. No. 4,275,055 to Nachtigal, et al., issued Jun. 23, 1981.

The molar ratio of protonatable amines to H⁺from the acid is preferably from about 1:0.3 to 1:1.2, and more preferably from about 1:0.5 to about 1:1.1.

In the conditioners of the invention, the level of cationic conditioning surfactant is suitably from 0.01 to 10, preferably from 0.05 to 5, more preferably from 0.1 to 2 percent by weight of the total composition.

Fatty Materials

Hair conditioner compositions according to the invention preferably additionally comprise fatty materials.

By “fatty material” is meant a fatty alcohol, an alkoxylated fatty alcohol, a fatty acid or a mixture thereof.

Preferably, the alkyl chain of the fatty material is fully saturated.

Representative fatty materials comprise from 8 to 22 carbon atoms, more preferably 16 to 22. Preferred fatty materials include cetyl alcohol, stearyl alcohol and mixtures thereof. Alkoxylated, (e.g. ethoxylated or propoxylated) fatty alcohols having from about 12 to about 18 carbon atoms in the alkyl chain can be used in place of, or in addition to, the fatty alcohols themselves. Suitable examples include ethylene glycol cetyl ether, polyoxyethylene (2) stearyl ether, polyoxyethylene (4) cetyl ether, and mixtures thereof.

The level of fatty material in conditioners of the invention is suitably from 0.01 to 15, preferably from 0.1 to 10, and more preferably from 0.1 to 5 percent by weight of the composition. The weight ratio of cationic surfactant to fatty material is suitably from 10:1 to 1:10, preferably from 4:1 to 1:8, optimally from 1:1 to 1:7, for example 1:3.

Hair conditioner compositions of the invention can also contain a cationic polymer. Suitable cationic polymers are described hereinabove in relation to shampoo compositions.

Hair oils are also suitable product forms according to the invention. Hair oils predominantly comprise water-insoluble oily conditioning materials. Lotions are aqueous emulsions comprising water-insoluble oily conditioning materials. Suitable surfactants can also be included in lotions to improve their stability to phase separation.

Compositions of this invention may contain any other ingredient normally used in hair treatment formulations.

Suspending Agents

Hair treatment compositions according to the invention such as shampoos suitably comprise from 0.1 to 5 wt % of a suspending agent. Suitable suspending agents are selected from polyacrylic acids, cross-linked polymers of acrylic acid, copolymers of acrylic acid with a hydrophobic monomer, copolymers of carboxylic acid-containing monomers and acrylic esters, cross-linked copolymers of acrylic acid and acrylate esters, heteropolysaccharide gums and crystalline long chain acyl derivatives. The long chain acyl derivative is desirably selected from ethylene glycol stearate, alkanolamides of fatty acids having from 16 to 22 carbon atoms and mixtures thereof. Ethylene glycol distearate and polyethylene glycol 3 distearate are preferred long chain acyl derivatives. Polyacrylic acid is available commercially as Carbopol 420, Carbopol 488 or Carbopol 493.

Polymers of acrylic acid cross-linked with a polyfunctional agent may also be used, they are available commercially as Carbopol 910, Carbopol 934, Carbopol 940, Carbopol 941 and Carbopol 980. An example of a suitable copolymer of a carboxylic acid containing a monomer and acrylic acid esters is Carbopol 1342. All Carbopol (trade mark) materials are available from Goodrich.

Suitable cross-linked polymers of acrylic acid and acrylate esters are Pemulen TR1 or Pemulen TR2. A suitable heteropolysaccharide gum is xanthan gum.

Further Conditioning Agents

Hair treatment compositions according to the invention such as shampoos and conditioners suitably contain further conditioning agents such as silicone conditioning agents and non-silicone oily conditioning agents.

Suitable silicone conditioning agents include polydiorganosiloxanes, in particular polydimethylsiloxanes which have the CTFA designation dimethicone. Also suitable for use in compositions of the invention (particularly shampoos and conditioners) are polydimethyl siloxanes having hydroxyl end groups, which have the CTFA designation dimethiconol. Also suitable for use in compositions of the invention are silicone gums having a slight degree of cross-linking, as are described for example in WO 96/31188. These materials can impart body, volume and stylability to hair, as well as good wet and dry conditioning. Also suitable are functionalised silicones, particularly amino-functionalised silicones.

Suitable non-silicone oily conditioning agents are selected from hydrocarbon oils, fatty esters and mixtures thereof.

The further conditioning agent is suitably present in shampoo or conditioner compositions at a level of from 0.05 to 10, preferably from 0.2 to 5, more preferably from about 0.5 to 3 percent by total weight of further conditioning agent based on total weight of the composition.

Hair treatment compositions of the invention may contain other optional ingredients for enhancing performance and/or consumer acceptability, such as fragrance, dyes and pigments, pH adjusting agents, pearlescers or opacifiers, viscosity modifiers, preservatives, and natural hair nutrients such as botanicals, fruit extracts, sugar derivatives and amino acids.

In addition to the antidandruff agents in the eutectic mixture further antidandruff agents may be present.

A preferred antidandruff agent in addition to that in the eutectic mixture is zinc pyrithione (ZnPTO).

The invention is further illustrated with reference to the following, non-limiting examples, in which all percentages are by weight based on total weight unless otherwise specified.

EXAMPLES

The following are lists of suitable eutectic mixtures for use with the invention:

TABLE 1 Molar ratios of active combinations containing an anti-dandruff agent, a menthol active and an organic acid, that combine to form a eutectic mixture. Materials Molar ratio Ketaconazole Menthol Phenol 1:1:1 Imidazole Menthol Phenol 1:1:1 Clotrimazole Menthol Phenol 1:1:1 Miconazole Menthol Phenol 1:1:1 Bifonazole Menthol Phenol 1:1:1 Climbazole Menthol Salicyclic acid 1:1:1 Ketoconazole Menthol Salicylic acid 1:1:1 Imidazole Menthol Salicylic acid 1:1:1 Miconazole Menthol Salicylic acid 1:1:1 Bifanazole Menthol Salicyclic acid 1:1:1 Climbazole Menthol Catechol 1:1:1 Ketoconazole Menthol Catechol 1:1:1 Imidazole Menthol Catechol 1:1:1 Clotrimazole Menthol Catechol 1:1:1 Miconazole Menthol Catechol 1:1:1 Bifonazole Menthol Catechol 1:1:1 Climbazole Menthol Benzoic acid 1:1:1 Imidazole Menthol Benzoic acid 1:1:1 Clotrimazole Menthol Benzoic acid 1:1:1 Miconazole Menthol Benzoic acid 1:1:1 PMEA Menthol Phenol 1:1:1 PMEA Menthol Sacilcylic acid 1:1:1 Ketaconazole Menthol Phenol 0.5:1:1 Ketaconazole Menthol Salicyclic acid 0.5:1:1 Ketoconazole Menthol Benzoic acid 0.5:1:1 Climbazole Menthol Phenol 0:5:1:1 Climbazole Menthol Catechol 0.5:1:1 PMEA Menthol Salicylic acid 0.5:1:1 Climbazole Menthol Chrysin 0.1:1:1 Climbazole Menthol Chrysin 0.5:1:1 Climbazole Menthol Chrysin 1:1:1 Climbazole Menthol Chrysin 1:1:0.5 Climbazole Menthol Chrysin 1:1:0.1 Climbazole Menthol Chrysin 0.5:1:0.5 Climbazole Menthol 0.25:1 Climbazole Menthol 0.5:1 Climbazole Menthol 1:1 Preparation of Eutectic Mixture and Melting Point Determination

Ketoconazole, menthol and salicylic acid were initially combined in a 1:1:1 molar ratio, and the molar ratio then further adjusted to determine the range of ratios over which eutectic mixtures could be formed. The formation of a eutectic mixture was confirmed by demonstrating a decrease in melting temperature of the mixture relative to that of the melting temperatures of the constituent actives individually.

The melting point of pure active samples (i.e. non-formulated actives) were determined using an Electrothermal Digital Melting Point measurement apparatus. Samples were held in glass capillary tubes and brought to a melt condition using a temperature ramp of 1° C./min. Melting temperature was measured when the sample formed a completely clear liquid.

FIG. 1 shows the melting temperatures for different molar ratio combinations of non-formulated ketoconazole, menthol and salicylic acid. ‘Keto’ represents ketoconazole only.

Melting point measurements were used to identify the molar ratios of triple active mixtures of ketoconazole, menthol and salicylic acid, that formed the optimum eutectic combinations (i.e. those nearest the eutectic point). In short, these combinations were characterised as those that lowered the melting temperature of ketoconazole and salicylic acid from 119.7° C. and 158.7° C. respectively, to lows of between 40° C. and 45° C. (note: the melting point of pure menthol is 29.7° C.). Specifically it is demonstrated in FIG. 1 that the molar ratios leading to a eutectic mixture were 0.25-2 ketoconazole:1 menthol:1 salicylic acid. Without being bound by theory it is thought that reduction in melting temperature demonstrates that strong supramolecular interactions (most likely H-bonding) between individual actives are occurring, resulting in the formation of an ‘active complex’ or eutectic mixture.

HPLC Measurement of Ketoconazole Deposition onto Artificial Skin

Ketoconazole (1-[4-[4-[[(2S,4R)-2-(2,4-dichlorophenyl)-2-(imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazin-1-yl]ethanone) is virtually insoluble in water, but soluble at ambient temperature in ethanol. For this reason, ketoconazole deposition in vitro was determined by ethanol extraction of the compound from an artificial skin model (Vitro-Skin™; representative of scalp skin), followed by HPLC measurement. Quantitation was made by reference to a standard curve.

Pre-cut artificial skin was sandwiched in a plastic ring support, with its rough topography facing up. Water (1.5 ml) was added to the plastic ring, followed by 0.5 ml of shampoo base, or conditioner base, containing the ketoconazole/menthol/salicylic acid mixture (see above). The mixture was then stirred with a teflon stirring rod, ensuring contact with the artificial skin surface, so as to mimic the massaging of the scalp by a consumer during hair washing. The shampoo/conditioner solutions were removed from the plastic ring with a dropper, ensuring that no liquor remained, and the artificial skin rinsed with 2 ml of distilled water, including 30 s of stirring as before. The rinsing water was then removed. Ketoconazole extraction was performed with ethanol (100%, 3 ml) with 30 s stirring. The resulting supernatant was filtered through a 0.45 μm PTFE filter into a standard HPLC vial. HPLC detection of ketoconazole was performed with Jones Genesis 25 cm×4.6 mm

C18 column containing a 60:40 mixture of 10 mM potassium dihydrogen phosphate and acetonitrile (flow rate 1 ml/min, 40° C.) and an Hewlett Packard Series 1100UV variable wavelength detector (set to 224 nm). Ketoconazole concentration (ppm) was measured directly from standard calibration curves.

Assessment of Formulation Bio-Efficacy (Malassezia Kill) by Vitro-Skin™ Assay

Formulation bio-efficacy was assessed using an in vitro substantivity assay which evaluates the effectiveness of actives in shampoo and conditioners using Malassezia furfur CBS 7019 as the organism.

Malassezia furfur for the inoculation of artificial skin were initially grown in Pityrosporum Broth, and added to molten agar slurry immediately prior to the inoculation of the Vitro-Skin™ at a final concentration of 1-3×10⁵ cells/ml. Vitro-Skin™ was placed onto a Modified Dixon Agar Plate (1 skin per plate), and 0.5 ml of agar slurry inoculum was gently pipetted onto the rough surface of the skin, in a film 1-2 mm deep. After the agar had gelled, the plates were placed in an incubator (32° C.) for 24 h. Following incubation, each piece of Vitro-Skin™ was carefully folded in half (inoculum on the inside) using sterile forceps, and placed a vial containing 10 ml of Butterfield's phosphate buffer (pH 7.2), 0.1% Triton X-100, 0.5% Tween and 0.08% lecithin. The vial was vortexed for 1 min (high setting), and 1 ml of this sample (10°) then added to 9 ml of 0.1% peptone (in water: 10⁻¹ sample). This sample was then serially diluted to 10⁻⁵ in 0.1% peptone. For immediate controls, 0.1 ml of 10⁰-10⁻⁴ dilutions were plated onto Modified Dixon Agar Plates. For 24 h incubated samples, 0.1 ml of 10⁰-10⁻⁵ dilutions were plated onto Modified Dixon Agar Plates, and incubated at 32° C. for 4-5 days. The number of colonies on each plate were then counted, and final numbers determined by multiplying by the appropriate dilution.

Enhancement of Ketoconazole Deposition and Malassezia Microkill Using Shampoo and Conditioner Formulations Containing a Eutectic Mixture of 0.1% Ketoconazole:0.05% Menthol:0.05% Salicylic Acid

Further evaluation of eutectic mixtures was completed using shampoo and conditioner formulations comprising eutectic mixtures having a molar ratio of 0.5 ketoconazole:1 menthol:1 salicylic acid (in these tests this translated to a formulation containing 0.1% ketoconazole:0.05% menthol:0.05% salicylic acid). The resulting solution was added to shampoo of formula 1 or a conditioner of formula 2. Mixtures were rolled for 24 h to allow dispersion of the active molecules.

Formula 1 Ingredient wt % SLES-1EO 14.0 Cocamidopropylbetaine 1.6 Jaguar C17¹ 0.2 Glydant² 0.2 ¹is Guar Hydroxypropyltrimonium Chloride ²is DMDM Hydantoin

Formula 2 Ingredient wt % Cetearyl Alcohol³ 5.0 Arquad 16-50⁴ 2.4 Crodozosoft DBQ⁵ 0.53 Hydroxyethylcellulose 0.2 Glydant² 0.4 Methylparaben 0.2 ³is cetyl alcohol and stearyl alcohol ⁴is cetrimonium chloride and isopropyl alcohol ⁵is quaternium 91

FIG. 2 demonstrates the effect of a eutectic shampoo formulation containing a 0.5:1:1 molar ratio of ketoconazole/menthol/salicylic acid on the deposition of ketoconazole. All actives were formulated in the shampoo formulation of formula 1. Key: 1) Shampoo only, 2) 0.2% ketoconazole, and 3) 0.2% total of a ketoconazole/menthol/salicylic acid eutectic mix (shaded). Note that the eutectic formulation contains only 0.1% ketoconazole (and 0.05% each of menthol and salicylic acid), but delivers a 3-fold improvement in ketoconazole deposition efficiency. This shows that the eutectic formulation enhances the amount of ketoconazole available for deposition from the shampoo formulation.

Likewise, FIG. 3 shows that a eutectic conditioner formulation (as per formula 2 above) containing a 0.5:1:1 molar ratio of ketonconazole/menthol/salicylic acid, increases the deposition efficiency of ketoconazole approximately 4.5-fold. Key: 1) conditioner only, 2) 0.2% ketoconazole, and 3) 0.2% total of a ketoconazole/menthol/salicylic acid eutectic mix (shaded). Note that the eutectic formulation contains only 0.1% ketoconazole (and 0.05% each of menthol and salicylic acid), Thus, the eutectic formulation also enhances the amount of ketoconazole available for deposition from a conditioner formulation.

FIG. 4 shows the effect of a eutectic shampoo formulation containing a 0.25:1 molar ratio of climbazole/menthol on the deposition of climbazole. All actives were formulated in the shampoo formulation of formula 1. Key: 1) Shampoo only, 2) 0.3% climbazole, and 3) 0.3% total of a climbazole/menthol eutectic mix (shaded). Note that the eutectic formulation contains 0.1% climbazole and 0.2% of menthol. Significantly enhanced deposition for climbazole is obtained.

To corroborate the observations reported in FIGS. 1 and 2, a shampoo formulation of formula 1 with a eutectic mix (a eutectic 0.5:1:1 molar ratio mix of ketoconazole/menthol/salicylic acid) was also assessed for microkill efficiency (i.e. Malassezia furfur kill; see above for details). FIG. 5 demonstrates the effect of this eutectic shampoo formulation containing a 0.5:1:1 molar ratio of ketoconazole/menthol/salicylic acid on microkill (Malassezia furfur kill). The key is as follows: 1) Shampoo only, 2) 0.2% salicylic acid, 3) 0.2% menthol, 4) 0.1% ketoconazole, 5) 0.2% ketoconazole, and 6) 0.2% total of a ketoconazole/menthol/salicylic acid eutectic mix (shaded). The data in FIG. 5 show that shampoo base, 0.2% salicylic acid, 0.2% menthol and 0.1% ketoconazole alone were relatively ineffective in terms of microkill. In contrast, 0.2% ketoconazole was highly effective, reflecting the classic dose-dependent response to ketoconazole. The data also show clearly that the eutectic formulation, which contains only 0.1% ketoconazole, delivers excellent microkill effectiveness. In fact, this formulation, is almost as effective 0.2% ketoconazole alone, and is 10-fold more effective than 0.1% ketoconazole alone. Thus enhanced deposition from the eutectic formulation is accompanied by enhanced microkill.

Finally, FIG. 6 shows the effect of a eutectic conditioner formulation containing a 0.5:1:1 molar ratio of ketoconazole/menthol/salicylic acid on microkill (Malassezia furfur kill). The key is as follows: 1) Conditioner only, 2) 0.2% ketoconazole, 3) 0.2% total of a ketoconazole/menthol/salicylic acid eutectic mix (shaded). Again, note that the eutectic formulation contains only 0.1% ketoconazole (and 0.05% each of menthol and salicylic acid). FIG. 6 shows that a conditioner base alone is ineffective in terms of microkill, whilst the eutectic formulation, which contains only 0.1% ketoconazole, is as effective as 0.2% ketoconazole alone. This replicates the effects seen with shampoo formulations, and shows that a eutectic formulation can deliver enhanced performance from different formulations/products. 

The invention of claimed is:
 1. A hair/scalp care composition comprising at least 2wt % of the total composition of a surfactant and 0.01 to 5% by wt. of a eutectic mixture, the eutectic mixture comprising an azole based antidandruff agent and menthol, wherein formation of said mixture is confirmed by a decrease in melting temperature of the mixture relative to that of melting temperatures of constituent actives individually.
 2. A hair/scalp care composition according to claim 1 in which the antidandruff agent is ketoconazole.
 3. A hair/scalp care composition according to claim 1 in which the eutectic mixture is a hair tertiary system.
 4. A hair/scalp care composition according to claim 1 in which the eutectic mixture further comprises an organic acid.
 5. A hair/scalp care composition according to claim 4 in which the organic acid is selected from the list consisting of salicylic acid, benzoic acid, and mixtures thereof.
 6. A hair/scalp care composition according to claim 4 in which the molar ratio of azole based antidandruff agent/menthol/organic acid within the eutectic mixture is from 0.1:1:1 to 2:1:1.
 7. A hair/scalp care composition according to claim 1 in which the eutectic mixture has a melting point below 45° C.
 8. A hair/scalp care composition according to claim 1 in which the surfactant is an anionic surfactant. 